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Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry

The role of phytochelatins (PC(n), metal-binding oligopeptides with the general structure (γGlu-Cys)(n)-Gly (n = 2–11) in metal detoxification is assumed to be based on immobilization of metals, which prevents binding of metals to important biomolecules. Although induction of phytochelatin synthesis...

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Autores principales: Scheidegger, Christian, Suter, Marc J.-F., Behra, Renata, Sigg, Laura
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Research Foundation 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277950/
https://www.ncbi.nlm.nih.gov/pubmed/22347879
http://dx.doi.org/10.3389/fmicb.2012.00041
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author Scheidegger, Christian
Suter, Marc J.-F.
Behra, Renata
Sigg, Laura
author_facet Scheidegger, Christian
Suter, Marc J.-F.
Behra, Renata
Sigg, Laura
author_sort Scheidegger, Christian
collection PubMed
description The role of phytochelatins (PC(n), metal-binding oligopeptides with the general structure (γGlu-Cys)(n)-Gly (n = 2–11) in metal detoxification is assumed to be based on immobilization of metals, which prevents binding of metals to important biomolecules. Although induction of phytochelatin synthesis has often been observed in algae upon exposure to metals, direct evidence for binding of the inducing metal to phytochelatins is scarce. In this study, a nano-electrospray ionization mass spectrometry (nano-ESI-MS) method is developed for identification and characterization of Pb(II)–PC(n) and Zn(II)–PC(n) complexes. Complexes of Pb(II) with standard PC(n) (n = 2–4; 0.25 mM Pb(II) and 0.5 mM PC(n)) were examined by nano-ESI-MS with respect to their stoichiometry. Pb–PC(n) mass spectra indicated the presence of the [M + H](+) peak of PC(n) and complexes with various stoichiometries. Analysis of Pb–PC(2) allowed the identification of four different complexes observed at m/z 746.10, 952.06, 1285.24, and 1491.20, corresponding to [Pb–PC(2)](+), [Pb(2)–PC(2)](+), [Pb–(PC(2))(2)](+), and [Pb(2)–(PC(2))(2)](+). Their m/z indicated coordination of Pb(II) by PC(2) through the thiol groups of PC cysteine and possibly carboxylic groups. For each of the standard PC(3) and PC(4), two different complexes were observed, corresponding to Pb–PC(3), Pb(2)–PC(3), Pb–PC(4), and Pb(2)–PC(4). The measured isotopic patterns were for all complexes identical to the theoretical isotopic patterns. Addition of Zn(II) (0.125–5 mM) to previously formed Pb–PC(2) complexes showed the appearance of the [Zn–PC(2)](+) complexes at m/z 602.05 and the decrease of the [Pb–PC(2)](+) peak. These findings corroborate the postulated Pb–PC complexes from a previous study using size exclusion chromatography of PC extracted from algae, as well as the concurrent formation of Pb–, Zn–, and Cu–PC complexes in algae.
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spelling pubmed-32779502012-02-17 Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry Scheidegger, Christian Suter, Marc J.-F. Behra, Renata Sigg, Laura Front Microbiol Microbiology The role of phytochelatins (PC(n), metal-binding oligopeptides with the general structure (γGlu-Cys)(n)-Gly (n = 2–11) in metal detoxification is assumed to be based on immobilization of metals, which prevents binding of metals to important biomolecules. Although induction of phytochelatin synthesis has often been observed in algae upon exposure to metals, direct evidence for binding of the inducing metal to phytochelatins is scarce. In this study, a nano-electrospray ionization mass spectrometry (nano-ESI-MS) method is developed for identification and characterization of Pb(II)–PC(n) and Zn(II)–PC(n) complexes. Complexes of Pb(II) with standard PC(n) (n = 2–4; 0.25 mM Pb(II) and 0.5 mM PC(n)) were examined by nano-ESI-MS with respect to their stoichiometry. Pb–PC(n) mass spectra indicated the presence of the [M + H](+) peak of PC(n) and complexes with various stoichiometries. Analysis of Pb–PC(2) allowed the identification of four different complexes observed at m/z 746.10, 952.06, 1285.24, and 1491.20, corresponding to [Pb–PC(2)](+), [Pb(2)–PC(2)](+), [Pb–(PC(2))(2)](+), and [Pb(2)–(PC(2))(2)](+). Their m/z indicated coordination of Pb(II) by PC(2) through the thiol groups of PC cysteine and possibly carboxylic groups. For each of the standard PC(3) and PC(4), two different complexes were observed, corresponding to Pb–PC(3), Pb(2)–PC(3), Pb–PC(4), and Pb(2)–PC(4). The measured isotopic patterns were for all complexes identical to the theoretical isotopic patterns. Addition of Zn(II) (0.125–5 mM) to previously formed Pb–PC(2) complexes showed the appearance of the [Zn–PC(2)](+) complexes at m/z 602.05 and the decrease of the [Pb–PC(2)](+) peak. These findings corroborate the postulated Pb–PC complexes from a previous study using size exclusion chromatography of PC extracted from algae, as well as the concurrent formation of Pb–, Zn–, and Cu–PC complexes in algae. Frontiers Research Foundation 2012-02-13 /pmc/articles/PMC3277950/ /pubmed/22347879 http://dx.doi.org/10.3389/fmicb.2012.00041 Text en Copyright © 2012 Scheidegger, Suter, Behra and Sigg. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
spellingShingle Microbiology
Scheidegger, Christian
Suter, Marc J.-F.
Behra, Renata
Sigg, Laura
Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title_full Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title_fullStr Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title_full_unstemmed Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title_short Characterization of Lead–Phytochelatin Complexes by Nano-Electrospray Ionization Mass Spectrometry
title_sort characterization of lead–phytochelatin complexes by nano-electrospray ionization mass spectrometry
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3277950/
https://www.ncbi.nlm.nih.gov/pubmed/22347879
http://dx.doi.org/10.3389/fmicb.2012.00041
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